It is often desired to protect sensitive data and software programs against unauthorized access and copying by thieves and hackers. Sensitive data can include passwords, account numbers, pin numbers, access codes, and other information that are used in financial transactions. Although data encryption/decryption methods are commonly used to secure sensitive data in financial transactions, thieves are learning the encryption methods and are sometimes able to break through the security. Furthermore, data and software can still be accessed prior to encryption. For example, a thief or hacker may still be able to physically penetrate electronic components and gain access to processors, various memory devices, and address/data busses that are used to communicate and process sensitive data.
To prevent sensitive data from being accessed in an unauthorized manner, various security modules and containers have been developed to enclose a circuit to be protected. A tamper detection circuit within the container is typically connected to the security layers to detect circuit tampering. Once a tamper condition has been detected, sensitive information stored in the circuit is quickly erased before it can be read by the possible attacker. Examples of such security modules are described in U.S. Patent Application Publication No. 2007/0018334, and in U.S. Patent Application Publication No. 2007/0038865.
However, the described methods for protecting electronic components have many limitations. Some involve complex or expensive technologies which are not conducive to mass production. Others provide inadequate protection. Alternative solutions are sought.